Magnetic release system for snow skis

ABSTRACT

An improved release system for snow skis utilizing magnetic force to releasably retain the boots of a skier in engagement with the skis so long as minimum preselected release force values are not encountered. A keeper plate is recessed in and attached to the sole of each ski boot for magnetic connection to a permanent magnet positioned in a channel member secured to each ski. Interfitted projections and recesses between the keeper plate and magnet effect reliable interconnection therebetween. Cooperable boot toe and heel retainer structures also are provided on each ski, as are release means for selectively disengaging a boot from the ski in response to specific skier demand.

United States Patent 1191 Olson et al.

1 1 MAGNETIC RELEASE SYSTEM FOR SNOW SKIS [76] Inventors: Donald M. Olson, 317 Lee St.,

Oakland, Calif. 94610; Michael A. McNeilly, 297 Mapache Road. Portola Valley. Calif. 94025 221 Filed: June 24, 1974 211 Appl. No.: 482.3117

[52] US. Cl 280111.35 M; 280/11.35 T [51] Int. Cl. A63C 9/08 [58] Field ofSearch 5280/1 1.35 M, 11.35 T.

280/1 1.35 K, 11.35 D, 11.35 A, 11.35 E. 230/1135 11. 11.35 C, 11.35 R

[ Dec. 23, 1975 3.687.471 8/1972 Sommer 280111.35 M ux 3.752.491 8/1973 Fend 2110/1135 K FOREIGN PATENTS OR APPLICATIONS 1,478,100 6/1969 Germany 2130/1135 M Primary Examiner-Robert R. Song Assistant ExaminerMi1ton L. Smith Attorney, Agent, or Firm-Flehr, Hohbach. Test. Albritton & Herbert 1 1 ABSTRACT An improved release system for snow skis utilizing magnetic force to releasably retain the boots of a skier in engagement with the skis so long as minimum preselected release force values are not encountered. A keeper plate is recessed in and attached to the sole of each ski boot for magnetic connection to a permanent magnet positioned in a channel member secured to each ski. lnterfitted projections and recesses between the keeper plate and magnet effect reliable interconnection therebetween. Cooperable boot toe and heel retainer structures also are provided on each ski. as are release means for selectively disengaging a boot from the ski in response to specific skier demand.

16 Claims, 13 Drawing Figures U.S. Patent Dec. 23, 1975 Sheet 1 of4 3,927,897

is @i x w\ 1 Q1 R 1 V I n U.S. Patent Dec. 23, 1975 Sheet 2 of4 3,927,897

U.S. Patent Dec.23, 1975 Sheet3 on 3,927,897

US. Patent Dec. 23, 1975 Sheet 4 of4 3,927,897

FIG- /3 MAGNETIC RELEASE SYSTEM FOR SNOW SKIS BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to the field of snow skis. More particularly, this invention relates to the field of devices for releasably retaining the boots of a skier in engagement with snow skis. Still more particularly, this invention relates to the field of ski release systems utilizing magnetic forces to maintain a skiers boots in operative engagement with his skis so long as predetermined release force values are not encountered.

Still more particularly, this invention relates to the field of magnetic snow ski release systems for safely maintaining a skier in operative engagement with his skis and for permitting disengagement of the skier's boots from the skis when predetermined forces are encountered, such as during a fall by the skier.

2. Description of the Prior Art Magnetic ski bindings have been known generally heretofore and reference is directed to the following patents for an illustrative showing of various bindings which are characteristic of the prior art: Sommer U.S. Pat. No. 3,353,835 dated Nov. 21, i967; Berta U.S. Pat. No. 3,437,345 dated Apr. 8, 1969; Larson U.S. Pat. No. 3,667,771 dated June 6, I972; and Sommer U.S. Pat. No. 3,687,471 dated Aug. 29, I972. Such patents are cited as illustrative of prior art utilizing magentic forces in various manners for operatively connecting a skier's boot with snow skis.

In addition to such patents, the following patents are illustrative of bindings which have utilized interfitted projections and recesses in conjunction with magnetic forces in ski binding systems: Kulick U.S. Pat. No. 3,318,6l dated May 9, I967; and Gottfried U.S. Pat. No. 3,357,719 dated Nov. 3, 1970.

However, none of the prior art references cited, nor any other prior art of which applicants are aware, discloses or utilizes the particular structural features and magnetic force concepts disclosed and claimed herein which provide the improved magnetic ski release system of the present invention. That is, while certain individual features disclosed herein may be shown generally in the prior art (such as the broad concept of utilization of magnetic forces in a ski binding system), the particular features and concepts emphasized and claimed herein are, so far as applicants know, novel in their combined utilization of established principles of magnetism and solid geometry. Thus, so far as applicants know, no prior art embodies a ski release system capable of functioning in the improved and reliable fashion of the present invention.

SUMMARY OF THE INVENTION This invention relates generally to an improved stepin type snow ski release system utilizing magnetic principles. Still more particularly, this invention relates to an improved ski release system which combines principles of permanent magnets and solid geometry.

Still more particularly, this invention relates to an improved ski release system in which a permanent magnet is attached to a snow ski and a cooperating keeper plate is recessed in and attached to the sole of a skiers boot, with one or more retaining buttons projecting from the magnet for releasable engagement within recesses formed in the boot keeper plate. That is, this invention relates to an improved magnetic ski release system in which magnetic forces of known values are employed in conjunction with principles of solid geometry and are applied with respect to projections and recesses formed in cooperable mating portions of components of a ski release system interposed between a ski and a skiers boot.

With the subject ski release system, a skier may become disengaged from a ski upon predetermined release force values becoming encountered during skiing, such as when the skier falls. While the subject release system is designed to release a skier under all emergency conditions commonly encountered during snow skiing, the subject release system is particularly well suited to safely release a skier from his skis during slow speed falls of the type which can be particularly harmful to skiers if ski release does not come about. The subject system also is designed to be equally effective for use by adults and children.

The subject ski release system, because of its relative simplicity and minimum number of parts, is relatively inexpensive to produce and is simple to mount upon skis.

From the foregoing, therefore, it should be understood that objects of this invention include the provisions of an improved ski release system for snow skis; the provision of an improved ski release system utilizing magnetic forces to releasably attach ski boots to skis; the provision of an improved magnetic ski release system which combines principles of the permanent magnet with principles of solid geometry to produce a safe, efficient and effective releasable connecting means between ski boots and snow skis; and the provision of an improved ski release system usable equally effectively by children and adults of various sizes and weights.

These and other objects of this invention will become apparent from a study of the following disclosure in which reference is directed to the appended drawings.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view through a snow ski and the release system of the present invention showing the same interposed between the ski and a ski boot illustrated in phantom lines.

FIG. 2 is a plan view of the subject release system taken in the plane of line 2-2 of FIG. 1.

FIG. 3 is a vertical sectional view of an enlarged scale relative to FIG. 1 taken in the plane of line 33 of FIG. 1.

FIG. 4 is a vertical sectional view on an enlarged scale relative to FIG. 1 illustrating details of the boot heel retainer structure forming part of the subject system.

FIG. 5 is an end elevational view of the heel retainer structure taken in the plane of line 5-5 of FIG. 4.

FIGS. 6 and 7 are a vertical sectional view and a plan view, respectively, of a modified embodiment of the boot heel retainer structure of the subject system.

FIG. 8 is a vertical sectional view through a toe portion of the subject system illustrating a modified toe retainer structure of the subject system.

FIG. 9 is a plan view of the modified embodiment of FIG. 8 taken in the plane of line 9-9 thereof.

FIGS. 10 through 13 are generally schematic views of cooperable magnetic components which illustrate the geometric principles utilized in the subject ski release system.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The improved ski release system of the present invention utilizes magnetic principles and employs such principles with principles of solid geometry for the purpose of creating a safe and effective release system for snow skis designed for use by skiers of all ages and sizes and levels of proficiency.

The subject magnetic ski release system is designed for effectiveness in conjunction with releasing a skier from his skis during the types of falls which heretofore have most frequently resulted in skier injury, namely slow speed or twisting falls which more conventional release systems are not capable of responding to without skier injury. However, effectiveness of the subject system is not limited to such falls but extends to all emergency conditions to which a skier may be subjected.

As will be described hereinafter, the ski release system of this invention includes three principal components or structures, namely (1) means for attaching a permanent magnet of improved character to a ski, (2) means cooperable with the magnetic means engaged with the sole of the ski boot and (3) means for retaining the boot heel in operative position relative to the ski. While the illustrated embodiments preferably utilize a fourth component, namely boot toe retainer means, such toe retainer structure preferably is incorporated into the cooperable principal components by means of which the magnetic means is retained on the ski and the ski boot is cooperably engaged with the magnetic means. Thus, a conventional and complex toe holddown means characteristic of many prior art bindings is not required in the present release system.

in the foregoing regard, reference is directed to FIGS. 1 through 5 for details of construction of a preferred embodiment of the subject magnetic ski release system. Such ski release system is generally designated 1 and is defined by the three principal components mentioned previously. Such components include means, generally designated 2, securing a magnet to the upper surface of a ski 3; means, generally designated 4, for operatively engaging a boot with the magnetic means; and boot heel retaining means, generally designated 6, for properly positioning the heel of a skier's boot (generally designated 7 and illustrated by dotted lines in H0. 1) in proper position on ski 3.

As noted previously, means for properly positioning and retaining the toe of boot 7 relative to the ski is incorporated into the aforementioned cooperable means 2 and 4 and will be described hereinafter in conjunction therewith.

As best seen in FIG. 2, the respective component structures of the ski release system are mounted in alignment with the longitudinal axis of the ski, generally at the mid-point thereof, in accordance with known practice.

As seen in FIGS. 1 and 3, means cooperable with the magnetic structure of the release system is attached to each of the skier's boots as shown. The sole 8 of the boot is provided (by molding or machining) with an elongated shallow channel 9 which extends for the major portion of the length of the boot sole between its toe 11 and heel 12. At a predetermined location or locations longitudinally of such channel, the boot sole is provided with at least one depression 13 for the purpose to be described. In the illustrated embodiment in 4 FIGS. 1 and 3, which is designed for adult use, two longitudinally spaced axially aligned depressions 13 are provided adjacent the toe and heel as illustrated.

The depth of channel 9 is determined by the dimensions of a boot keeper plate 14 received in such channel as seen in FIGS. 1 and 3. The keeper plate 14 and the channel 9 are laterally and longitudinally dimensioned to substantially close tolerances so that the keeper plate is snugly receivable within such channel.

Suitable means are provided for securely retaining the keeper plate in engagement with the sole of the boot and in the illustrated embodiment a series of screw fasteners 16 are employed for that purpose. If desired, a suitable adhesive, such as epoxy resin adhesive, may be interposed between the keeper plate and the boot sole to further enhance secure interengagement of the keeper plate to the boot. Such an adhesive is desirable because it imparts moisture sealing capability to the system and prevents moisture from seeping between the boot plate and the boot sole.

The keeper plate is provided with at least one projection 17 (two such projections are utilized in the illustrated embodiment) which the aforementioned depressions 13 in the boot sole were provided to accommodate. Such projections 17 are formed in accordance with close predetermined tolerances and contour considerations to provide precisely designed concave recesses 18 in the undersurface of the keeper plate for cooperable engagement with predetermined portions of the magnetic structure secured to the ski.

in the embodiment illustrated, one recess 18 is provided adjacent each of the toe and heel margins of the boot keeper plate. The precise locations of such depressions relative to the toe and heel margins of the keeper plate is not critical. However, in a keeper plate having an overall length of approximately ll inches, it has been found preferable to locate the center of each depression just slightly in excess of 2 inches from the opposite toe and heel margins of the keeper plate so that the same are symmetrically oriented relative to the longitudinal center thereof. Thus, the keeper plate and its associated structures forms and defines one principal component 4 of the magnetic release system of the present invention.

The material chosen for the keeper plate may vary so long as a magnetic material is chosen which has sufficient strength to resist the force encountered during skiing. A suitable magnetic material for the keeper plate is Type 430 stainless steel which has been found particularly effective therefor.

Another principal component structure of the subject release system defines the means by which magnetic force may be applied to the keeper plate to retain the same, and the boot attached thereto, engaged with ski 3 until predetermined release force values are encountered. Such magnetic means is defined by a series of cooperable components including an elongated open metal channel member 21 of slightly less length than boot keeper plate 14.

Metal channel 21 is U-shaped in cross section and, as seen from FIGS. 1 and 3, the lateral dimensions thereof tapers or increases gradually and progressively from adjacent the toe portion 23 thereof to the heel portion 22 thereof. That is, as seen in FIG. 3 while the opposed sidewalls 24 and 26 of the channel extend generally at right angles to the flat base 27 thereof, such walls converge towards each other towards the toe portion 23 of the channel.

A toe retainer piece 28 is secured to the base of the channel by a series of tack welds and closes off the toe end of the channel. The toe retainer member is provided with a generally triangular projection 29 which is to be engaged with a reversely and downwardly bent marginal end portion 30 of the boot keeper plate 14 as best seen in FIG. 1. That is, the toe retainer 28 of channel member 21 is contoured and dimensioned to interfit with the reversely bent marginal toe portion 31 of the boot keeper plate to maintain the keeper plate and channel member longitudinally aligned when interengaged.

The heel end of the channel member 21 is closed off by a retainer piece 31 extending thereacross and held in place by a screw fastener 32 which extends through the base 27 of the channel into the retainer 21.

The toe retainer piece 28 and heel retainer piece 31 may be formed of any suitable material, such as lightweight aluminum alloy or the like. Preferably, the channel member 21 is formed from the same material as the boot keeper plate 14, although any sturdy magnetic material may be utilized for boththe channel member and the keeper plate.

Positioned within and substantially filling the channel member 21 for its full length, width and depth is at least one permanent magnet, generally designated 36. In the illustrated embodiment such magnet 36 is defined by two discrete but cooperable sections, designated 37 and 38. While a single magnet could be utilized, it has been determined that two separate sections are preferable to permit and accommodate flexing of ski 3 during use thereof so that magnet damage during such flexing will be precluded. In that regard, the line of division between the magnet sections 37 and 38 is identified by reference numeral 39 in FIGS. 1 and 2. Such line of division preferably is located centrally of the release system when mounted on ski 3.

Because of the magnetic attraction of the magnet sections with the channel member 21, no additional means is required to hold the magnet sections 37 and 38 in place in such channel. However, the retainer pieces 28 and 31 at the toe and heel margins of the channel member preclude any lateral shifting of the magnet sections during use of the release system.

As best seen in FIG. 3, the channel member 21 is held in place by means of two or more screw fasteners 43 extending through holes provided in the base 27 of the channel member at spaced locations therealong. The screw fasteners are threadedly interengaged in threaded inserts 44 positioned in the ski 3 and extending partly therethrough in known fashion. Thus, the channel member 21 is securely and rigidly held in place on the upper surface of the ski.

Although not illustrated in the drawings, preferably a thin layer of plastic, such as Teflon plastic, (Teflon is the trademark of E. I. duPont deNemours & Co. for its brand of polytetrafluoroethylene plastic) about 6 mils thick, is applied to the upper surface of the magnet sections 37 and 38 and is baked in place thereon to seal the surface of the magnet against moisture seepage and to protect such magnet upper surface against damage when the boot keeper plate is not in position thereover.

In that regard, preferably the upper surfaces of the magnet sections are positioned at a level slightly below the upper marginal edges of the side walls 24 and 26 of channel member 21 as seen in FIG. 3. Thus, a thin gap or air space, designated 41 in FIGS. 2 and 3, exists between the upper surface of the magnet and the undersurface of the boot keeper plate when the components of the release system are interengaged. Preferably such gap is of the magnitude of 25 to 30 mils in dimension.

While the magnetic material from which magnet sections 37 and 38 are formed may vary, oriented barium ferrite magnetic material is preferred for the stated purpose. Characteristics of such material are well known and are set out in detail in the American Society of Metals Handbook, pages 779 et seq, and reference is directed thereto for the particular features of barium ferrite which make the same particularly well suited for the intended purpose. In that general regard, barium ferrite is particularly well suited for use in the subject release system because of its ability to resist shock and temperature differentials without adverse effects on its magnetic capabilities. Additionally, its reasonable cost compared to other magnetic materials also makes it particularly attractive for the stated purpose.

As pointed out hereinbefore in conjunction with the citation of exemplary prior art utilizing magnetic force in conjunction with ski bindings of various types, it should be understood that the mere utilization of magnetic force without additional considerations would not normally make such concept effective in a ski release system. Thus, the present invention incorporates features which also call into play principles of solid geometry to create a safe ski release system effective under all normal operating conditions.

Such means which incorporate geometric principles into the subject release system are designed to project from the magnetic structure attached to the ski 3 for cooperable interengagement with the recesses 18 formed in the under surface of the boot keeper plate as previously described. Such projecting means is defined by at least one contoured indexing button, the number of which is determined by particular skiing requirements. In the illustrated embodiment two such indexing buttons 46 are provided, one adjacent each the toe and heel margins of the release system.

The spacing of the buttons 46 from each other corresponds to the longitudinal spacing between the centers of the recesses 18 as described previously. Thus, when the boot keeper plate 14 and magnet 36 are interengaged as seen in FIG. 1, the indexing buttons 46 are directly received within recesses 18. The purpose of such projecting buttons is to insure secure shift-proof interengagement between the release system components until predetermined release forces are encountered. Such buttons also assist in effecting such interengagement during initial contact between the boot keeper plate and the magnetic means by guiding the keeper plate into proper engagement on the ski.

Each button 46 is provided with a recessed shank 47 which is frictionally received within a vertical bore 48 provided in each of the magnet sections 37 and 38 as best seen in FIG. 3. Preferably the shank 47 of each button is slightly larger than its associated bore 48 so that the same will be retained therein without requiring adhesive to maintain the same securely in place. Preferably each button is formed from flexible yet sturdy material, such as Teflon plastic, the strength ofwhich is enhanced by filling the same with approximately 20 or 30% glass fibers.

The cooperable specially designed interengagable contour of the buttons 46 and recesses 18 will be described hereinafter. That is, the contour of the head of each button 46 and of each recess 18 in the boot keeper plate is specifically designed to utilize the aforementioned principles of magnetic force and solid geometry to produce an effective ski binding release system.

The third principal component of the release system will be described prior to detailing the cooperable magnetic force and geometrical considerations. A heel retainer structure, that is, the assembly for cooperating with the magnetic means in retaining the boot heel properly positioned relative to the ski, is illustrated in FIGS. 1, 2, 4 and 5. Such heel retainer structure may be adjustably set to overcome toe and heel ski bending moments until desired release force values are encountered and exceeded. Such heel retainer structure further provides means to disengage the ski boot from the ski by overcoming the magnetic force upon skier demand, such as when a skier wishes to voluntarily release himself from the skis.

The heel retainer unit comprises a yoke member 51 defined by a flat base 52 and a pair of opposed parallel arms 53 and 54, respectively, as best seen in FIG. 5. The yoke is formed from any suitable sturdy metal, such as the material from which the keeper plate 14 and channel member 21 are formed. The base 52 is provided with a suitable screw receiving aperture through which a screw fastener 56 extends and which is threadedly received within a screw threaded insert 57 positioned and secured in the ski rearwardly of the channel member 21 as seen in FIGS. 1 and 4.

An elongated release lever 57 is mounted for pivotal movement between the arms 53 and 54 of the yoke by means of shaft 58 extending transversely of the yoke arms adjacent their upper margins. Shaft 58 is held in place by retainers 59 and 61 peened over the shaft ends as seen in FIG. 5.

Adjacent its outer end 62, lever 37 is provided with a countersunk recess 63 for receiving therein the tip of a ski pole so that the outer end of the lever may be pivoted clockwise when viewed in FIG. 4. When thus pivoted, the opposite inner end 64 of the lever, which normally underlies the heel portion 12 of the boot sole 8, is similarly pivoted clockwise to physically urge the boot heel upwardly to thereby effect selective disengagement of the boot from the magnetic means mounted on the ski by overcoming the magnetic attraction between the magnet and boot keeper plate 14.

When it is desired to re-engage the boat with the magnet, it is merely necessary to position the boot keeper plate for interengagement with the indexing buttons 46 mentioned previously and to step downwardly on the heel to engage inner end 64 of lever 57 with the boot heel. Such interengagement will pivot the lever in a counterclockwise direction when viewed in FIG. 4.

Adjustable means is provided to overlie the upper surface of the heel portion 12 of the boot sole, designated 66 in FIG. 4. Such adjustable means, as best seen from FIGS. 4 and 5, comprises a generally L-shaped retainer bracket 67 having a flange portion 68 at the upper end thereof. The bracket is formed with an elongated slot 69 as best seen in FIG. through which an adjustment screw 71 extends into a threaded insert 72 secured in lever 57 generally beneath the pivot shaft 58 described previously. Preferably a lock washer 73 is interposed between the retainer bracket 67 and the lever to insure positive positioning of the bracket against upward or downward movement when the screw 71 is positioned in place. Thus, by locating the flange portion 68 of the retainer bracket in a predetermined location determined by the thickness of the heel portion 12 of the boot sole so that the upper portion 66 of the sole contacts the under surface of the flange, the heel retaining structure and the boot sole may be securely interengaged in the manner described.

The entire retainer structure is positively retained in engagement with the boot sole when in the position shown in FIG. 4 by locking means provided in conjunction therewith. Such locking means in the illustrated embodiment comprises detent structure defined by a recess 76 formed in the periphery of pivot shaft 58 as best seen in FIG. 4. A ball detent 77 is normally engaged in recess 76 to preclude pivotal movement of the lever 57 in the clockwise direction when viewed in FIG. 4. Such ball detent is spring urged to its locking position by means of a plunger 78 movably positioned within a bore 79 extending longitudinally of lever 57. The outer end of the plunger engages the ball detent 77 and urges the same into the detent recess as seen in FIG. 4.

The plunger in turn is urged against the ball detent by a coil spring 81 which is interposed between the plunger and an adjustment screw 82 threadedly and adjustably received in an outer threaded portion 83 of the bore 79. Preferably the adjustment screw 82 has a spring centering projection 84 on its inner end which is received within the confines of spring 81 to maintain the spring properly centered in bore 79 and its threaded extension 83.

It should be understood that upon rotating the adjustment screw 82 in either the clockwise or counterclockwise direction, the spring pressure applied by spring 81 to the ball detent 77 may be selectively increased or decreased so that the hold down force applied by the heel retaining unit to the boot heel may be increased or decreased, depending upon the release force value determined by the size of skier utilizing the subject release system. At its outer end the adjustment screw 82 is provided with a screw driver slot 86 or equivalent means for effecting easy rotation of the adjustment screw to increase or decrease spring pressure on the ball detent.

Additionally, preferably the adjustment screw is provided at its outer end with a projecting portion 87 having a plurality of indicating rings 88 thereon which provide a visual indication of the amount of pressure, in accordance with predetermined values, applied by the adjustment screw to the spring 81 and thereby to the ball detent 77. Thus, by viewing the position of the adjustment screw relative to the outer surface 89 of lever 57 into which bore 79 extends, a visual determination may readily be made of the amount of spring pressure applied to ball detent 77. If desired, the rings 88 may be color coded to permit easier visual determination of the pressure setting of the adjustment screw 82.

To prevent unwanted shifting of the heel retaining structure relative to the upper surface of the ski, a pin 91 is positioned between the base 52 of yoke 51 and the ski for the stated purpose. Preferably the base 52 of yoke 51 is provided with a transverse slot 92 as best seen in FIG. 4 through which a safety retainer strap (not shown) may be positioned to be secured around the ankle of the skier in known fashion to prevent separation of the ski and loss thereof from the skier's boot should the subject release system free the boot from the ski during a fall, for example.

In FIGS. 6 and 7, a modified heel structure is illustrated which functions in generally the same fashion as the heel retainer structure described in FIGS. 1, 4 and 5. However, the embodiment of FIGS. 7 and 8 differs therefrom principally in the structure provided for engaging the upper surface 66 of the boot heel portion 12 and the release lever 57 thereof. In that regard, corresponding reference numerals are utilized in FIGS. 6 and 7 for components corresponding to those previously described.

A further difference in the FIGS. 6 and 7 embodiment resides in the construction of the adjustment screw 82'. While such adjustment screw includes a spring centering projection 84' received within spring 81, the outer surface of such adjustment screw is provided with a generally conventional slotted head portion which does not include the color coded rings 88 mentioned previously. Pressure applied by the spring 81 to the ball detent 77 is adjustable and the amount of such pressure may be determined, for example, by noting the number of screw threads visible on the adjustment screw head relative to the outer surface 89 into which the bore 79 extends.

In the embodiment of FIGS. 6 and 7, the retainer bracket 67 is replaced by a rotatable heel hold-down wheel 96 mounted on and overlying an upper inner surface 97 of the lever 57 as best seen in FIG. 6. Interposed between the hold-down wheel 96 and surface 97 is a bearing washer 98. The hold-down wheel 96 is held in place by a headed screw fastener 99 threadedly received in and locked in place in a threaded bore 101 formed in the lever 57 adjacent its inner boot contacting end.

It should be understood that hold-down wheel 96 is free to rotate in clockwise and counterclockwise directions when viewed in FIGS. 7 in response to release forces being exerted thereon by the boot heel during a skiing fall for example. The function of hold-down wheel 96 is the same as the function of the previously described flange 68 of hold-down bracket 67 but the hold-down wheel is designed to minimize the friction between the hold-down element and the boot heel when the same is subjected to release forces during a fall.

FIGS. 8 and 9 illustrate a modified embodiment of the toe retainer structure of the subject release assembly. The toe retainer unit designated 28' in FIG. 8 is provided with a lateral rearwardly extending base flange 101 which terminates in an upwardly projecting button 102 which is received within a recess 103 formed by the frontmost marginal portion 105 of the base of channel member 21 which receives the magnet therein. The flange portion 101 of the toe retainer 28 underlies such channel member portion 105 as best seen in FIG. 8.

As seen in FIG. 9, the retainer unit 28' has its flange portion 101 formed generally in the shape of a semicircle to interfit with a correspondingly shaped recess 104 formed in the base portion of the channel member as seen in FIG. 9. As illustrated in FIG. 8, the reversely bent toe margin 30 of the boot keeper plate intert'its with the modified toe retainer unit 28' to maintain the toe of the boot properly positioned during normal skiing usage. However, such interengagement of toe retainer 28 or its counterpart retainer 29 does not prevent ease of separation forwardly and in both lateral directions when predetermined release forces are exceeded as determined by the magnetic values of the magnet 36.

As mentioned previously, the subject release system utilizes a combination of magnetic force principles and solid geometry principles to provide the improved release features of this invention.

As applied to ski bindings, certain magnetic principles of a basic nature have been illustrated in FIG. 10. In that regard, it is well known that when two magnets of opposite polarity, designated 111 and 112 in FIG. 10, are in direct North-South (N-S) polar contact with each other as illustrated, the magnetic force M resisting separation thereof along the vertical or Z axis (that is, the axis which is parallel to the direction of magnetization) is the strongest. Magnetic forces resisting motion or separation along the X or Y axes, or the rotational theta (6) axis are substantially weaker (for example, approximately two-thirds or less) than the magnetic force existing along the Z axis.

To prevent movement along any of the mentioned weaker magnetic axes X, Y or 0 between the magnetic circuit defined by magnet sections 37 and 38 and the boot keeper plate 14 until a desired predetermined force value is encountered, the aforementioned indexing buttons 46 are provided in interengagentent with correspondingly contoured recesses 18 in the undersurface of the keeper plate. As seen in FIGS. 2, 3 and 9, each indexing button is formed in the shape of a truncated cone, although a segment of a sphere also may be utilized.

Each indexing button is thus formed with an inclined plane outer surface which works conjunctively with the correspondingly contoured recess 18 in the keeper plate and with the magnetic attraction of the release system, coupled with the weight of the skier, to establish a force value required to cause movement of the keeper plate in relation to the magnetic circuit of the assembly. This arrangement responds to the classic inclined plane equation treating with forces acting at a predetermined angle to an inclined plane as illustrated in FIG. 11, as follows:

FIGS. 12 and I3 apply the magnetic principles described previously with respect to FIG. 10 to the particular construction of the subject invention so that the geometric considerations applicable to the inclined plane of FIG. 11 are utilized in conjunction with the particular structural features of the present magnetic release system, as follows. I

With a permanent magnet circuit of desired magnetic pull MP (a constant value) control of the release force (Fr) is accomplished by establishing the desired slope (angle) of the inclined plane face of the indexing button, thereby permitting the system to release at a predetermined and preselected force which is dependent only upon the weight W of the skier. By designing the system to utilize readily interchangeable indexing buttons having different inclined plane faces, release forces of high, medium, low or any desired value may be provided for, in line with the following principles.

When a force acts at any angle X to the inclined plane and the inclined plane angle is Y degrees relative to the ski upper surface (horizontal), the release force 1 I desired or encountered may be determined as follows, discounting friction, and referring to FIG. 13:

cos x release along any axis or combination of axes except the Z axis.

EXAMPLE 1 W and MP applied to only one ski and using an indexing button having an inclined face angle Y of 30, the force to release is:

W-i-MPX sin Y 265 X cos x osss [53 pounds EXAMPLE 2 W and MP are evenly distributed on both skis and using an indexing button having an inclined face angle Y of 30', release force is:

W and MP applied to only one ski and using an indexing button with Y angle of release force is:

W+ MP Xsin l 70.8 pounds EXAMPLE 4 W and MP are evenly distributed on both skis, and using an indexing button with Y angle of 15, release force is:

%W+MPXsinY cosX 46.7 pounds From the foregoing illustrations it should be appreciated that the subject magnetic release system may be readily and easily tailored in accordance with skier size to provide a particular release designed to safely permit separation of the skier from his skis under emergency conditions.

While the preferred embodiments of the magnetic ski release system illustrated and described herein previously utilize an elongated magnet defined by two sections and two release buttons in conjunction therewith, for release systems requiring less release force, such as in a child's binding or a binding for a very lightweight adult, it is contemplated that only a single magnet section and a single release button would be required. In such case, the release button would be positioned rearward of the longitudinal center of the magnet channel member 21 with a corresponding recess being formed in the under surface of the boot plate also being located rearwardly of the central location of the boot keeper plate. In the circumstances described where only a single button would be utilized, the shape of the button preferably would be changed from the frusto-conical configuration when taken in horizontal cross-section to 5 an oval or other configuration which would assist in proper longitudinal alignment of the boot relative to the ski while retaining the inclined plane considerations mentioned previously. The magnetic-geometric considerations would still apply in such case, however.

It should be understood that with all embodiments of the release system disclosed herein, interengagement of the boot keeper plate and the magnet structure is easily effected merely by interengaging the toe hold-down structure components and then moving the keeper plate and boot rearwardly until the indexing buttons enter and are held in the recesses by magnetic force. The cooperable contour of the buttons and recesses makes such an interengagement simple to effect and produces an essentially self-centering or self-locating feature in the subject system.

Having thus made a full disclosure of preferred embodiments of an improved magnetic ski release system, reference is directed to the appended claims for the scope of protection to be afforded thereto.

25 We claim:

1. A magnetic release system for snow skis comprismg A. an elongated keeper plate to be attached to the sole of a skiers boot,

B. an elongated permanent magnet structure generally co-extensive with said keeper plate to be attached to a ski, and

C. separable indexing structure interposable between said plate and said magnet structure comprising 1. a low friction indexing button integral with said magnet structure and having a head portion projecting thereabove having the surface of an inclined plane exposed to said plate,

2. said head portion of said indexing button being of smaller size then said magnet structure and overlying only a limited portion thereof, and

3. a recess formed in said plate contoured in accordance with the size and configuration of said projecting head portion of said button,

4. whereby said button and recess when interengaged resist lateral separation of said plate and magnet structure until predetermined release forces are encountered.

2. The release system of claim 1 which further includes D. heel retainer means to be attached to said ski rearwardly of said magnet structure for releasably holding down the heel of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.

3. The release system of claim 1 which further includes D. toe retainer means interposed between said plate and said magnet structure for releasably holding down the toe of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.

4. A magnetic release system for snow skis which utilizes combined principles of magnetic force and r l3 geometry comprising A. an elongated keeper plate to be attached to the sole of the skiers boot,

I. a recess formed in said plate,

B. an elongated permanent magnet structure generally co-extensive with said keeper plate to be attached to a ski, and l. a low friction indexing button integral with and projecting from said magnet structure toward said plate,

2. said button having a generally frusto-conical head compatibly contoured with the configuration of said recess,

3. said head of said indexing button being of smaller size than said magnet structure and overlying only a limited portion thereof,

C. said button and recess when interengaged resisting lateral separation of said plate and magnet structure until predetermined release forces (Fr) are encountered in accordance with the following formula:

W+ MP X sin Y F cos X where W weight of the skier using system MP magnetic pull of magnet structure X =angle of force on the indexing button surface Y angle of indexing button surface relative to the ski.

5. A magnetic release system for snow skis compris- A. a keeper plate to be attached to the sole of a skiers boot,

B. a permanent magnet structure generally coextensive with said keeper plate to be attached to a ski, and

C. separable indexing structure interposable between said plate and said magnet structure comprising 1 apair of longitudinally spaced low friction indexing buttons integral with said magnet structure each of which has a generally frusto-conical head portion projecting above said magnet structure,

2. said head portions of said indexing buttons being of smaller size than said magnet structure and overlying only limited portions thereof, and

3. a pair of longitudinally spaced generally frustoconical recesses formed in said plate contoured in conformance with the size and shape of said buttons,

4. the spacing between the centers of said recesses corresponding to the spacing between the centers of said buttons,

5. whereby said buttons and recesses when interengaged resist lateral separation of said plate and magnet structure until predetermined release forces are encountered.

6. The release system of claim 5 in which said buttons and recesses are contoured to resist separation of said plate and magnet structure until predetermined release forces (Fr) are encountered in accordance with the following formula:

W+MPXsin Y cos where W weight of the skier using system MP magnetic pull of magnet structure X =angle of force on the indexing button surface Y angle of indexing button surface relative to the ski.

7. The release system of claim 5 in which each of said indexing buttons is formed from a low friction plastic such as Teflon.

B. The release system of claim 5 in which said magnet structure comprises 1. an elongated channel member to be attached to the upper surface of a ski, and

2. an elongated permanent magnet positioned in and substantially filling said channel member,

3. said indexing buttons being removably received in bores formed at predetermined locations in said magnet.

9. The release system of claim 8 in which said magnet is formed in two discrete sections so that said magnet structure can resist flexing of said ski without damage thereto.

10. The release system of claim 8 in which said magnet is formed from a shock resistant and temperature resistant magnetic material such as barium ferrite.

11. The release system of claim 8 which further includes D. heel retainer means to be attached to said ski rearwardly of said magnet structure for releasably holding down the heel of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.

12. The release system of claim 8 which further includes D. toe retainer means interposed between said plate and said magnet structure for releasably holding down the toe of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.

13. The release system of claim 11 in which said heel retainer means comprises 1. a yoke member to be secured to said ski rearwardly of said magnetic structure,

2. a release lever pivotally mounted on said yoke member and having an end portion thereof positionable beneath the heel of a boot when said boot is engaged with said ski through said release system, and

3. a hold-down member engaged with said lever and spaced vertically from said end portion thereof for overlying said boot heel when said boot and ski are engaged.

14. The release system of claim 13 in which said hold-down member comprises a vertically adjustable hold-down bracket secured to said lever.

15. The release system of claim 13 in which said hold-down member comprises a rotatable wheel secured to said lever above said end portion thereof.

16. The release system of claim 13 in which said heel retainer means further includes 4. spring urged adjustable detent structure for maintaining said lever in a boot heel hold-down position with said lever end portion underlying said boot heel and said hold-down member overlying said boot heel. 

1. A magnetic release system for snow skis comprising A. an elongated keeper plate to be attached to the sole of a skier''s boot, B. an elongated permanent magnet structure generally coextensive with said keeper plate to be attached to a ski, and C. separable indexing structure interposable between said plate and said magnet structure comprising
 1. a low friction indexing button integral with said magnet structure and having a head portion projecting thereabove having the surface of an inclined plane exposed to said plate,
 2. said head portion of said indexing button being of smaller size then said magnet structure and overlying only a limited portion thereof, and
 3. a recess formed in said plate contoured in accordance with the size and configuration of said projecting head portion of said button,
 4. whereby said button and recess when interengaged resist lateral separation of said plate and magnet structure until predetermined release forces are encountered.
 2. said head portion of said indexing button being of smaller size then said magnet structure and overlying only a limited portion thereof, and
 2. said button having a generally frusto-conical head compatibly contoured with the configuration of said recess,
 2. The release system of claim 1 which further includes D. heel retainer means to be attached to said ski rearwardly of said magnet structure for releasably holding down the heel of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.
 2. an elongated permanent magnet positioned in and substantially filling said channel member,
 2. a release lever pivotally mounted on said yoke member and having an end portion thereof positionable beneath the heel of a boot when said boot is engaged with said ski through said release system, and
 2. said head porTions of said indexing buttons being of smaller size than said magnet structure and overlying only limited portions thereof, and
 3. said indexing buttons being removably received in bores formed at predetermined locations in said magnet.
 3. a hold-down member engaged with said lever and spaced vertically from said end portion thereof for overlying said boot heel when said boot and ski are engaged.
 3. The release system of claim 1 which further includes D. toe retainer means interposed between said plate and said magnet structure for releasably holding down the toe of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.
 3. a recess formed in said plate contoured in accordance with the size and configuration of said projecting head portion of said button,
 3. a pair of longitudinally spaced generally frusto-conical recesses formed in said plate contoured in conformance with the size and shape of said buttons,
 3. said head of said indexing button being of smaller size than said magnet structure and overlying only a limited portion thereof, C. said button and recess when interengaged resisting lateral separation of said plate and magnet structure until predetermined release forces (Fr) are encountered in accordance with the following formula:
 4. A magnetic release system for snow skis which utilizes combined principles of magnetic force and geometry comprising A. an elongated keeper plate to be attached to the sole of the skier''s boot,
 4. whereby said button and recess when interengaged resist lateral separation of said plate and magnet structure until predetermined release forces are encountered.
 4. spring urged adjustable detent structure for maintaining said lever in a boot heel hold-down position with said lever end portion underlying said boot heel and said hold-down member overlying said boot heel.
 4. the spacing between the centers of said recesses corresponding to the spacing between the centers of said buttons,
 5. whereby said buttons and recesses when interengaged resist lateral separation of said plate and magnet structure until predetermined release forces are encountered.
 5. A magnetic release system for snow skis comprising A. a keeper plate to be attached to the sole of a skier''s boot, B. a permanent magnet structure generally coextensive with said keeper plate to be attached to a ski, and C. separable indexing structure interposable between said plate and said magnet structure comprising
 6. The release system of claim 5 in which said buttons and recesses are contoured to resist separation of said plate and magnet structure until predetermined release forces (Fr) are encountered in accordance with the following formula:
 7. The release system of claim 5 in which each of said indexing buttons is formed from a low friction plastic such as Teflon.
 8. The release system of claim 5 in which said magnet structure comprises
 9. The release system of claim 8 in which said magnet is formed in two discrete sections so that said magnet structure can resist flexing of said ski without damage thereto.
 10. The release system of claim 8 in which said magnet is formed from a shock resistant and temperature resistant magnetic material such as barium ferrite.
 11. The release system of claim 8 which further includes D. heel retainer means to be attached to said ski rearwardly of said magnet structure for releasably holding down the heel of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.
 12. The release system of claim 8 which further includes D. toe retainer means interposed between said plate and said magnet structure for releasably holding down the toe of said boot when said plate and magnet structure are interengaged but which does not prevent separation of said plate and magnet structure when said predetermined release forces are encountered.
 13. The release system of claim 11 in which said heel retainer means comprises
 14. The release system of claim 13 in which said hold-down member comprises a vertically adjustable hold-down bracket secured to said lever.
 15. The release system of claim 13 in which said hold-down member comprises a rotatable wheel secured to said lever above said end portion thereof.
 16. The release system of claim 13 in which said heel retainer means further includes 